Circuit breaker



Aug.y 8, 1939. w, A- ATWQQD 2,169,085

CIRCUIT BREAKER Filed Dec. A17, 1936 3 Shets-Sheet l In Ventor: Winfield A-Atwooql,

FS i-ils Attorng.

Allg. 8, 1939. A ATWQOD 2,169,085

CIRCUIT BREAKER Filed Deo. 17, 1936 3 Sheets-Sheet 2 Inventorn Winfield A. Atwoo d,

is Attorme.

Aug. 8, 1939. w A, ATWQOD 2,169,085l

CIRCUIT BBEAKER Filed Dec. 17, 1936 3 Sheets-Sheet 3 Inventor: Winfield A-Atwood,

i-iis Attovng'.

Patented 8, 1939 'f PATENT OFFICE' CIRCUIT BREAKER Winfield A.A Atwood, Yeadon, Pa.,l assignor to General Electric Company, a corporation of NewYork Application neeeinber 17, 193s, serial Ne.116,413.

My invention relates to` circuit breakers, more particularly to combined automatic and manual circuit breakers in which the circuit controlling contacts are manually operable between open'and closed circuit positions andare automatically operable to open circuit position upon the occurrence Vof predetermined current conditions, and hasY for an objectthe provision of a circuit breaker of this character Which'is simple and reliable in its operation and which is inexpensivel to construct.

' Various circuitbreakers ofthis character, have heretofore been provided, many of which are to a large extent satisfactory for the purposes for l5 which they aredesigned. Such circuit breakers have found considerable application in thecontrol of distribution and feeder circuits and it is highly desirable in such cases that the circuit breakers not only be capable of handling large currents, but also be extremely compact and rugged in their construction. Something is yet to be desired, therefore, in circuit breakers of this character and'it is' a further object of my invention to provide a simpleeand reliable circuit breaker of this type which is of rugged and compact construction.

In carrying out myvinvention in one form, I l

vprovide a circuit breaker comprising a rotatable shaftfor controlling the' circuit breaker contacts, 3o the shaft having noncircular ends arranged respectively to engage corresponding n noncircular apertures in a pair of crank members, together with manually and automatically operable means for rotating the crank members to causemovement of the circuit controlling contacts between open and closed circuit positions.' More speciiically, I provide a multiple pole circuit breaker in which a plurality of rotatable axially spaced.

shafts are provided'for operating a plurality of switch members each of the shafts having noncircular 'ends the shafts being interconnected by :insulatingl crank members disposed -in the spacesfbetween the shafts with the ends of the shafts 55 pendently of the overcenter spring means. The

v'z claims. (c1. zoo-ss) tripping member is normally restrained against movement by current responsive latch means and is release for movement upon the occurrence. of predetermined current conditions. VLMeans are also provided for automatically varying the ef- 5 fective lever arm throughwhich the tripping spring force is applied to the tripping member as the tripping member moves from its latched position.

For a` more complete understanding of my in- 10 vention, reference should now be had to the drawings, in which Fig. 1 is a sectional elevational view of a circuitbreaker embodying my invention; Fig. 2 is alplan view, partly in section, of the circuit breaker shown in Fig. 1 Withl certainr parts 15 broken away, more clearly to illustrate the constructional details; Figs. 3 and v4 are fragmentary enlarged views similar to Fig. 1 showing the circuit breaker in different operating positions; and Fig. 5 is a. detail view in exploded perspective of 20 Acertain operating elements of the circuit breaker.

` Referring now to'the drawings, I have shown my invention in one form as applied to a circuit breaker comprising a base I0 formed of molded insulating material and having a plurality of walls 25 Illa which cofoperate with similar Walls I2 in a cover member I I for separating the individual poles of the circuit breaker, the left-hand end of the cover II being open, as shown in Fig. 1. Disposed on the base I0 adjacent the open end of 30 the cover II is a sub-base I3 which supports the tripping unit to vbe described hereinafter and which is provided with a cover member I 4, the sub-base I3 and thel cover member I4 serving-A to close the open end of the cover II. Mounted 35 on thebase I 0 betweenthe outer walls of the cover II and the inner walls I2 thereof are a plurality of compression chamber type interrupter 'units I5 and an operating mechanism I6 which is disposed between the trip unit carried by the 40 sub-base I3 and the interrupter unit for the middle pole of the circuit breaker.v

These interrupter units I5 form no part of my invention and are particularly described and claimed in U. S. Patent'No. 2,133,158 to D. W. ver 45 Planckand J. W, Seaman, issued October 11, 1938.

Sinceeach of the interrupter units I5 is identical in construction; only one of these units ,will be described and for thepurposes of the present invention, the interrupter units may be described as comprising Walls of pressure resistant material arranged to form a compression chamber, the Wall of the interrupter unit adjacent the operating mechanism comprising 'a plurality of sup- 55 2 ,y porting members `I1 and I8 which are formed of conducting material, preferably die-cast aluminum. As shown best in Fig. 5, these supporting members i1 and I8 include upstanding p0rtions which are provided with transverse grooves I9 and 28, respectively, the supporting member I1 being provided with an aperture 2l which intersects the groove I9. When the members I1 and I8 are secured together inf face to face relation, for example, by means of suitable dowel ber and the compression chamber is completed,

by means of a cup-shaped member 26, the open end of which is secured'to the supporting member I1. Secured to the shaft 24 intermediate the bearing portions is a switch member 21 which extends through the aperture 2 I in the supporting member I1 and carries a movable contact 28 which is arranged to engage astationary contact 29 supported within the compression chamber on an arcing horn 38 which is in turn supported on a conducting stud 3l which extends through and a is insulated from the horizontally extending portion of the support I1.

. Thus.' it will be seen that the-circuit through each pole of the circuit breaker extends (Fig. 1) from a. terminal member 32 adjacent the righthand end of the base I0 by way of a conductor 33, the conducting stud 3|, thearcing horn 38, the stationary and movable contacts 29 and 28, and through a exible conductor 34, one end of which is connected to the contact 28 and the other end of which is connected to the conducting supporting member I8. The supporting member I8 thus forms a portion of the electrical circuit, which circuit extends `from the supporting member I8 through the trip unit by way of suitable conductorsf35 and 36 to a terminal member 31 disposed on the left-hand end of the base I0.

As shown, the three Ainterrupter units I are disposed in side. by side relation so that the respective shafts 24 are arranged in axially spaced relation, and as shown best in Fig. 5, as these axially spaced shafts arev mechanically interconnected and electrically insulated from each other by means of a pair of insulating crank disks 38 which are disposed in the spaces between the shafts 24. Each of these crank members or disks 38 is provided with non-circular recesses or apertures 39 in the opposite lfaces thereofint'o which the adjacent noncircular ends of the shafts 24 extend, the respective opposite ends of the shaft 24 for the center interrupting unit extending intothe'apertures 39 in the inner faces of the' disks 38 and the inner ends of the shafts'.

24 foreach of the outer interrupting units extending into the' apertures 39 in the outer faces of the disks 3e.

lThe supporting member I8 for the center pole breaker is supported. This operating mechanism, as shown, comprises aninverted U-shapedoperating member 4I which straddles the supporting member I8, the lower ends of the'legs of the U,shaped member being pivotally supported on pins 42 which'extend outwardly from thebase yportion of the U`shaped supporting member I8 and the upper yoke portion of the member 4I carries an operating member or handle 43' which is formed of vsuitable insulating material and which extends through an aperture 44 in the circuit breaker cover` I I.

Intermediate the ends of the legs, the U-shaped Y operating member 4I is provided with a pair of inwardly extending pins 45f which support the respective adjacent ends of a pair of overcenter springs 46, the opposite ends of which are secured to suitable outwardly extending pins 41 carried by the side plates of a U-shaped toggle member 48. As shown,'this toggle member comprises a pair of side plates connected together by a cross member 49 and is pivotally mounted on a pin 58 (Figs. 1, 3, and 4) which extends through suitable apertures 5I in the toggle member 48 and through an aperture 52 in the portion' 40 of the supporting member I8.

This toggle member 48, as shown best in Fig. 5, is likewise provided with apair of outwardly extending pins 53 which are pivotally engaged by a pair of parallel links 54 which constitute the other link of the toggle and which are secured to a shaft or rod 55 which extends between the crank members 38, the opposite ends of the shaft 55 being disposed in suitable apertures 56 (see Fig. 5) in the crank members. It will thu's be seen gether for simultaneous operation to actuate the switch member 21 between its open and closed circuit positions in response to movement of the handle 43.

In Fig. l, the handle 43 is shown in its closed circuit position and it will be observed that the overcenter springs 46 bias the toggle members 48 and 54 to their made position which corresponds to the closed circuit positions of the switch members 21. In order manually to operate the switch members 21 to their open circuit positions, it is necessary only to move the handle 43 from the position shown in Fig. 1 to the position shown in Fig, 3, the consequent rotation of lthe operatling member 4I about its pivot 42, thereby carrying the left-hand ends of the overcenter springs 46 downwardly across the pivot pins 50 of the toggle link 48 so as to reverse the bias exerted by the overcenter springs Von, the toggle links.

As soon as the overcenter springs 46 pass overcenter relative to the pivot pins 50, the toggle link 48 will be rotated in a clockwise direction about the pivot 50 from the position shown in Fig. 1 to the position shown in Fig.` 3 so as to break the toggle and rotate the cranks 38, the shafts ,24 andy the switch members 21 to the open cir-w cuit ypositionlshown in Fig. 3. Obviously, the

circuit breaker may be reclosed by returning the handle 43 toward the position shown in Fig. l soA as to move the overcenter springs 46-up wardly across the pivot piny 50 and again reverse the bias on the toggle link 48.,

During operation of circuit breakers of this type, Vit is sometimes'found that conditions may arise in which the circuitLQcontrolling contacts may partially weld or stick and accordingly the overcenter springs may not be suiiifciently strong to effect opening movement of the circuit oontrolling contacts in response tomovement of the ythat the crank members 38 are connected tooperating handle. In order to ensure that the contacts will be positively opened whenever the operating handle is moved to its open circuitposition, I provide a pair of links 55a which'are eonnected to the shaft 55 and provided with elongated slots into which extend suitable pins 56a carried by the legs of the U-shaped operating member 4I. It will be apparent that if the cranks 38 are not operated in a counter-clockwise direction by the overcenter springs and the toggle means when the handle 43 is moved in a counterclorckwise direction from the closed circuit position shown in Fig. l, the pins 56a will engage the left-hand ends of the slots in the links 55a so as positively to move the cranks 38 in a counterclockwise direction. -As soon as the cranks 38 start to move in this direction, thefovercenter springs 46 will of course be effective through the toggle links 48 and 54 to complete themovement of the cranks to their open circuit position.

In addition to the manual operating means just described, means are provided for automatically operating the switch members 21 to their open circuit positions independently of thekhandle 43 upon the occurrence of predetermined current conditions. This automatic operating means includes a tripping member 51 which, as shown in Fig. 5, comprises a pair of spaced apart plates connected together adjacent their opposite ends by suitable pins '58 and 59 and provided with elongated slots 60 which movably support the opposite ends of a pin 6| to which is secured one end of a tripping spring 62, the opposite end of the spring 62 being secured to a finger 63 formed integrally with thesupporting member I8. The

` tripping member 51 is rotatably supported on a pin 64 which extends through an aperture 65 in the portion 40 of the supporting member I8, the extending end of the pin 64 providing stops for the toggle member 48 (Fig. l). It will be observed that the slots 6U extend substantially radially from the pivot pin 64 for a purpose which will be more fully described hereinafter.

Normally, the tripping member 51 is restrained against the bias of the tripping spring 62 by a latch member 66 which is pivotally mounted on a shaft 61 extending outwardly from the portion 40 of the supporting frame I8, a torsion spring 68 which surrounds the shaft 61 being provided for biasing the latch 66 to the position shown best in Figs. 1 and 3, in which position one side of the latch 66 is engaged by a pin 69 which extends outwardly from the tripping member 51. In this position, the lower end of the latch 66 is disposed in the path of movement of a roller 18 which extends outwardly from the tripping member 51 adjacent the pin 69 so as to prevent movement of the tripping member 51 from the position shown in Figs. 1 and 3.

Adjacent its other end, the tripping member 51 carries a roller 1I which is supported on the pin 59 and which is arranged to engage the cross portion 49 of the toggle member 48 so as to operate the toggle member 48 about its pivot pin 58 in a clockwise direction against the force exerted by the overcenter springs 46 to break the toggle and open the circuit breaker contacts whenever the tripping member 51 is released for movement in accordance with the bias of the tripping spring 62. It will be observed that with the tripping member 5T restrained in the positions shown in Figs. l and 3, the pin 6I, to which is connected the tripping spring 62 engages the innermost ends of the slots 6U and accordingly the force of the tripping spring 62 is applied to the tripping member 51 to produce a rotating moment through a minimum lever arm. As soon asthe tripping member 51 is released for movement in a clockwise direction about its pivot to the position shown in Fig. 4, the pin 6I moves along the slots 6I] and comes to rest in the outermost ends of the slots, thus automatically increasing the elective lever arm through which the force of the spring 62 is applied to the tripping member 51. By reason of this arrangement, I am enabled to obtain a minimum latching force while at the same time I obtain a maximum tripping force.

It will be apparent that as the tripping member 51 rotates the toggle link 48 from the closed circuit position shown in Fig. l to the open circuit position shown in Fig. 4, the right-hand ends of the overcenter springs 46 will be carried overcenter relative to the pivot pins 42 of the U- shaped operating member 4I and accordingly, the bias exerted on the operating member 4I will be reversed and accordingly the handle 43 will be operated in a counter-clockwise direction from the closed circuit lposition shown in Fig. 1. As shown, the operating member 4I lis provided adjacent its upper end with a transversely extending roller 12 which is disposed to engage the tripping member 51 so as to arrest the movement of the operating handle 43 in the mid-position shown in Fig. 4. Likewise, it will be observed that movement of the tripping member 51 and the toggle link 48 in a clockwise direction about their pivots is limited by engagement of the cross portion 49 of the toggle link 48 with the upstanding portion 4I) of the Lil-shaped frame I8.

In order to reclose the circuit breaker after automatic operation to the open circuit position, it is only necessary to move the operating handle 43 in a counter-clockwise direction from the position shown in Fig. 4 to the open circuit position shown in Fig. 3. As the operating handle 43 is moved in this direction, the roller 12 carried by the operating member 4I rotates the tripping member 51 in a counter-clockwise direction about its pivot to the position shown in Fig. 3 and as soon as the roller 18 passes below the end of the latch 66, the spring 68 rotates the latch from the position shown in Fig. "4 to the latching position shown in Fig. 3, whereupon the tripping member 51 is again restrained against movement in accordance with the bias of the tripping spring 62. The circuit breaker may now be closed by moving the handle from the position shown in Fig. 3 to the position shown in Fig. 1, as described above.

Although any suitable current responsive means may be provided for operating latch 66 from its latching position to release the tripping member 51', I have shown for purposes of illustration a shock-proof electromagnetic trip unit which embodies certain novel features described and claimed in a copending application of Joseph W. Seaman, Serial No. 78,179, filed May 6, 1936, entitled Circuit breakers, now Patent 2,067,792 issued January 12, 1937, and in a copending application of Robert W. Smith, Serial No. 78,177, led May 6, 1936, entitled Circuit breakers, now Patent 2,067,797 issued January 12, 1937.

As shown, this trip unit is mounted on the sub-base I3 and comprises a pair of spaced apart frame plates 13 between the upper ends of which is pivotally supported a U-shaped releasing member, one leg of which comprises a striking portion 14 and the other leg of which comprises a latching portion 15 and a resetting portion 16.

'I'his releasing member is normally biased for movement in a. yclockwise direction about its pivot pin 11 by a torsion spring 18 and is rei breaker. Asshown best in Fig. 2, this shaft 1S which are formed of insulating material.

is provided adjacent the middle pole of the circuit breaker with a notch 8|) and with an extending arm 8|, the opposite outer ends of the shaft 19 which extend over the outer poles of the circuit breaker being provided -with operating arms 82 Likewise, the shaft 19 -is provided with a biasing spring which normally biases the trip shaft 19 to the position shown, in which position the latching portion 15 of the releasing member engages the periphery of the shaft adjacent the notch 80.

In order that the trip shaft 19 may be rotated in a clockwise direction, to release the latching portion 15 of the releasing member for movement through the notch 80, in response to predetermined current conditions in any one of the circuit breaker poles, the trip unit is provided with a plurality of electromagnetic devices, one of which is connected in each pole cir-l cuit of the circuit breaker, each of these electromagnetic devicesbeing arranged to engage one of the operating arms 8| or 82 on the trip shaft 19. As is more fully described in the above-referred to Seaman application, each of the electromagnet devices comprises a magnetizable fra-me 84 which is'provided with an energizing winding 85, one end of which is connected to the conductor 35 and the other end of which is connected to the conductor 36, and with a balanced-armature 86 which is pivoted on the frame 84. 'Ihis balanced armature 86 is 'provided with a shock-spring 81 of .the type particularly described and claimed in 'the above-referred to Smith application and carries adjacent its upper end an adjustable member or screw 88 arranged to engage the associated operating arm 8| or 82 on the trip shaft 19` when the armature 86 is operated in a counter-clockwise direction about its pivot. Normally the armature 86 is biased tothe unattracted position shown by a spring (not shown), oner` end of which is connected to an adjustable member 89 carried by the upper end of the armature 86.

It will now be apparent that upon the occurrence of predetermined current conditions in any pole of the circuit breaker, one or more of the armatures 86 will be attracted upon a predetermined energization of the 'associated winding 85 and the adjustable member 88 will engage the associated operating arm 8| or 82 on the trip shaft 19 so as to rotate the trip shaft .in a clockwise direction and thereby release the latching portion 15 of the releasing member for movement through the notch 80. As soon as the latching portion of the releasing member is released for movement through the notch A8l), the spring 18 rotates the releasing member in a clockwise direction about its pivot 11, whereupon the striking portion 14 of the releasing member strikes the upper end of the latch 66 a hammer blow and rotates the latch 66 in a clockwise direction f reset the releasing member as the tripping mem- Y ber moves to its tripping position and for this purpose the tripping member is provided with a roller 90 which is arranged to engage the resetting portion 16 of the releasing member so `as immediately to return 'the releasing member to its latched position shown inthe drawings. As soon as the circuit breaker opens, the energizig windings of the electromagnetic devices are de-energized and accordingly the armatures 86 immediately return to their biased position shown, whereupon the trip shaft 19 is rotated to its latching position by the spring 83 to re-engage the latching portion 15 of the releasing member.

Thus, the releasing member of the trip unit is immediately reset and latched in its normal position and as soon as the operating handle 43 is actuated to reset the trip member 51, the roller l9|) moves out of engagement with the resetting portion 16 of the releasing member so that the releasing member is free to move immediately to its releasing position if an overload condition still exists when the circuit breakerl is reclosed.

While I have shown a particular embodiment of my invention, it will be understood, of course, that I do not wish to be limited thereto since many modifications may be made and I, therefore, contemplate by the appended claims to cover any suchY modifications as fall within the true spirit and scope of my invention.

' What I claim as new. and desire to secure by Letters Patent of the United States is:

1. A circuit breaker comprising a base formed of insulating material, terminal members arranged on the respective opposite ends of said base, a U-shaped frame formed of a material having a high electrical conductivity, means for securing the yoke of said U-shaped frame to said,

base intermediatesaid terminals with the legs of said U spaced longitudinally of said base, a pair of relatively movable contacts, means including a rotatable shaft for supporting one of said contacts for movement between open and closed circuit positions, means including one leg of said frame for rotatably supporting said shaft, conductor means connecting said one Contact to said Ione leg of said frame and for connecting the other of said contacts to said one terminal, operating means for said shaft supported on said frame between said (legs, current responsive means disposed between said frame and a terminal at the opposite end of said base for actuating said operating means, and conductor means connecting said current responsive means to said other terminal and to the other leg of said frame whereby said frame is electrically connected in the circuit through the breaker.

2. In a circuitbreaker, the combination of a tripping member movable between a latched position and a tripping position, a tripping spring, connecting means for applying to said tripping member through a predetermined lever arm the force of said spring, whereby said tripping member is biased for movement to said tripping position, latch means for normally restraining said tripping member in said latched position and for releasing said tripping member for movement to said tripping position, and vmeans including said connecting means for automatically varying said lever arm as said tripping member moves to said tripping position.

3. In a circuit breaker, the combination of a tripping member pivoted for movement between a latched position and a tripping position, a

' tripping spring, means for connecting' said spring said tripping member through a predetermined lever arm, means for restraining said tripping member in said latched position against the force exerted by said spring and for releasing said tripping member for pivotal movement to said tripping position, and means for automatically adjusting said connecting means to vary said lever arm as said tripping member moves to said tripping position.

4. In a circuit breaker, the combination of a tripping member pivoted for movement between a latched position and a tripping position, said tripping member having a slot therein extending substantially radially with respect to said pivot point, a pin disposed in said slot, a tripping spring connected to said pin for exerting on said tripping member a moment which depends upon the strength of said spring and the position of said pin in said slot, means normally latching said tripping member in said latched position wherein said pin engages the inner end of said slot and for releasing said tripping member for rotation to said tripping position, said pin duringsaid rotation moving along said slot automatically to increase the lever arm through which the force of said spring is applied to said tripping member.

5. A circuit breaker comprising a base of insulating material, terminal members arranged on the respective opposite ends of said base, a frame formed -of av material having a. high electrical conductivity, means for securing said frame to said base intermediate said terminals, a pair of relatively movable contacts, means including a rotatable shaft for supporting one of said contacts for movement between open and closed circuit positions, means including said frame for rotatably supporting said shaft, conductor means connecting said one contact to said frame and for connecting the other of said contactsvto said one terminal, toggle operating means between said shaft and said frame, an operating handle mounted on said frame, an overcenter spring connecting said handle to said toggle, a tripping member pivotally mountedA on said frame, current responsive means for normally restraining said tripping member in one position, said tripping member having a slot extending substantially radially with respect to its pivot point, a pin disposed in said slot, a tripping spring connected to said pin for exerting on said tripping member a moment which depends upon the position of said pin in said slot, said pin engaging the inner end` of said slot when said tripping member is secured by said current responsive means, but when said tripping member is released said pin moves to the other end of said slot to increase the lever arm through which the force of said spring -is applied to said tripping member, and means carried by said tripping member for engaging and operating said toggle against the force applied by saidovercenter spring.

6. A circuit breaker comprising a pair of relatively movable contacts, a frame, an operating member pivotally mounted on said i'rame, a contact actuating 4toggle having one link thereof pivoted on said frame and another link operatively connected to one of lsaid contacts, overcenter spring means connected to said operating member and one of said toggle links for operating said toggle to actuate said Contact between lopen and closed circuit positions with a vsnap action, a tripping member pivotally mounted on said frame for movement between a latched position and a tripping position, said tripping member having a slot therein extending substantially radially with respect to the pivot of said tripping member, a pin in said slot, a tripping spring connected to said pin for applying a moment 'to said tripping member dependent upon the position of said pin in said slot, current responsive means for normally restraining said tripping member in said latched position against the tension of said spring and for releasing said tripping member in response to predetermined current conditions for movement to said tripping position, and means carried by said tripping member for engaging one of said toggle links to operate said toggle against the force applied by said overcenter spring means, said pin during the pivotal movement of said tripping member moving along said slot to increase the lever arm through which the force of said'spring is applied to said tripping member.

7. A circuit breaker comprising an enclosing casing, a movable switch member in said casing, a shaft'extending through said casing for operating said switch member, the ends of said shaft extending from opposite sides of said casing, a pair of crank members secured to opposite ends of said shaft, an operating rod connecting the ends of said crank members together, a frame,

an operating member pivotally mounted` on said frame, a toggle having one link thereof pivoted on said frame and another link operatively connected to said rod, overcenter spring means connected to said operating member and said toggle for operating said toggle to actuate said switchl member between open and closed circuit positions with a snap action, a tripping member pivotally mounted on said frame for movement between a latched position and a tripping position, said tripping member having a'slot therein extending substantially radially with respect to the pivot of said trip-ping member, a connecting member movable in said slot, a tripping spring connected to said connecting member for applying a moment to said tripping member dependent upon the position of said connecting member in said slot, current responsive means for normally restraining 'said tripping member in said latched position against the tension of said spring and for releasing said tripping member in response to predetermined current conditions for movement to said tripping position, and means carried by said tripping member for engaging and operating said toggle against the force applied by said overcenter spring means, said connecting member .during the pivotal movement of said tripping member moving along said slot to increase the lever arm through which the forceof said spring is applied to said tripping member.

WINFIELD A. ATWOOD. 

